Potential role of bone morphogenetic protein-15 in zebrafish follicle development and oocyte maturation.
Bone morphogenetic protein (BMP)-15 is a member of the transforming growth factor beta (TGF-beta) superfamily and is closely related to growth and differentiation factor (GDF)-9, both structurally and functionally. In mammals, BMP-15 is predominantly produced by oocytes and exerts important regulatory functions within the ovary, such as promoting early folliculogenesis, preventing premature luteinization and enhancing cumulus cell expansion. The role of BMP-15 in mammalian ovary differs between monoovulatory and polyovulatory species. Recent studies in zebrafish have provided initial evidence that BMP-15 is also an important regulator of ovarian functions. BMP-15 is produced by the zebrafish ovary throughout follicle development and maturation. In vitro studies using zebrafish follicles have revealed that incubation with recombinant human BMP-15 or over-expression of BMP-15 in oocytes results in an inhibition of gonadotropin- and maturation inducing hormone (MIH)-induced oocyte maturation. Conversely, immnunoneutralization with BMP-15 antiserum or silencing of BMP-15 expression using morpholino antisense oligonueclotides enhances oocyte maturation. A key step in BMP-15 action is the sensitivity of follicles to MIH. In vivo injection of BMP-15 antiserum causes a significant decrease in maturation-incompetent (insensitive to MIH) small early growth phase follicles and a concomitant increase in mature follicles. These findings support a role in BMP-15 in preventing precocious oocyte maturation in zebrafish. We propose that the suppression of premature oocyte maturation by BMP-15 may be important to maintain oocyte quality and subsequent ovulation and fertilization.
Peng
Chun
C
Department of Biology, York University, Toronto, Canada. cpeng@yorku.ca
Clelland
Eric
E
Tan
Qian
Q
D000818:Animals; D055430:Bone Morphogenetic Protein 15 / Q000737:chemistry / Q000378:metabolism*; D005260:Female; D009865:Oocytes / Q000254:growth & development*; D009866:Oogenesis; D006080:Ovarian Follicle / Q000254:growth & development* / Q000378:metabolism*; D015027:Zebrafish / Q000254:growth & development* / Q000378:metabolism*
D055430:Bone Morphogenetic Protein 15